Answer
Александр
To solve this task, you need to translate the text information into mathematical form. The friends' costs in mathematical form are:
John = 2 Strategy + 4 FPS + 6 RPG
Alex = 3 Strategy + 3 FPS + 5 RPG
Noah = 4 Strategy + 2 FPS + 3 RPG
We don't know the price of the games.
So we have to compare the number of purchased games.
Let's sum up John and Noah's expenses:
John + Noah = 6 Strategy + 6 FPS + 9 RPG
If no one used the discount, then these costs are equal to two Alex.
Let's check this.
2 * Alex = 6 Strategy + 6 FPS + 10 RPG
John + Noah < 2 * Alex
Comparing, we notice that the two Alex's have one more RPG.
It follows that Alex took advantage of the discount.
Answer: Alex.